Apparatus and method for co-extruding multi color plastics

ABSTRACT

The present invention is the apparatus and method for producing a plastic sheet having a pattern produced in a layer therein. The plastic sheet is a single layer sheet or a multi-layer sheet. The pattern is produced by mixing two or more plastic extrudants together in a mixer. The pattern is visible in the layer containing the two or more plastic extrudants because an at least one of the plastic extrudants is at least partially transparent. The mixer used to produce the pattern includes a housing having an end configured to expel the mixture of the two or more extrudants through a plurality of outlets. The mixer further comprises a rotatable shaft and at least one projection coupled to the shaft and rotatable with the shaft, the at least one projection configured to orient the mixture of the two or more extrudants relative to the plurality of outlets in the housing. The mixer further comprising a thrust bearing configured to couple an end of the shaft to the housing.

FIELD OF THE INVENTION

[0001] The present invention relates to the production of a plasticsheet and the process and apparatus for producing the plastic sheet andin particular to the production of a plastic sheet having a decorativeappearance and the process and apparatus for producing the plastic sheetwith the decorative appearance.

BACKGROUND

[0002] Various products have been produced by vacuum forming a plasticsheet into the desired shape of the product. Example products includeslides for outdoor play equipment, showers, food trays and huntingaccessories. The plastic sheet used in the vacuum forming processtypically has an aesthetic side and a non-aesthetic side. The plasticsheet has generally had uniform coloration on both the non-aestheticside and the aesthetic side.

[0003] The plastic sheet is often made from at least two layers ofextruded plastic. The first layer is a base layer that is made fromrecycled plastic and provides the non-aesthetic side. The second layeris a colored layer which contains the coloration for the aesthetic sideof the plastic sheet. The use of multiple layers reduces cost byallowing manufacturers to reuse scrap plastic for the base layer(non-aesthetic side) and to minimize the amount of new plastic needed tocreate the aesthetic side.

SUMMARY OF THE INVENTION

[0004] The present invention is the apparatus and method for producing aplastic sheet having a pattern produced therein.

[0005] In one exemplary embodiment, an apparatus for producing anon-linear pattern from a mixture of at least two extrudants in anextrusion process comprising a housing having a first end and a secondend and an interior region. The first end of the housing being adaptedto receive the mixture of at least two extrudants and the second end ofthe housing being configured to expel the mixture of the at least twoextrudants in a non-linear pattern. The second end of the housingincluding a plurality of outlets to selectively expel the mixture. Theapparatus further includes a shaft having a first end and a second end.The first end of the shaft located proximate to the first end of thehousing and the second end of the shaft located proximate to the secondend of the housing. The shaft being rotatable relative to the housingabout an axis. The apparatus further includes at least one projectioncoupled to the shaft and rotatable with the shaft. The at least oneprojection configured to orient the mixture relative to the plurality ofoutlets in the second end of the housing. The apparatus furthercomprising a thrust bearing configured to couple the second end of theshaft to the second end of the housing to permit the expulsion of themixture in a non-linear pattern as the mixture is oriented relative tothe plurality of outlets.

[0006] In another exemplary embodiment, an apparatus for producing amulti layer plastic extrudant comprising a first extruder configured toextrude a first plastic extrudant, a second extruder configured toextrude a second plastic extrudant, the second plastic extrudant beingat least partially transparent and a third extruder configured toextrude a third plastic extrudant. The apparatus further comprises amixer coupled to the second extruder and the third extruder. The mixerbeing configured to produce a mixture of the second plastic extrudantand the third plastic extrudant, the mixture including a non-linearpattern. The apparatus further comprising a co-extrusion blockcomprising a first channel and a second channel, wherein the firstchannel is coupled to the first extruder to receive the first plasticextrudant to produce a first layer and wherein the second channel iscoupled to the mixer to receive the mixture of the second plasticextrudant and the third plastic extrudant to produce a second layer. Thesecond layer containing the non-linear pattern wherein the third plasticextrudant of the mixture is visible within the second layer due to thesecond plastic extrudant of the mixture being at least partiallytransparent.

[0007] In another exemplary embodiment, the mixer of the precedingembodiment comprising a housing having a first end and a second end andan interior region. The first end of the housing being configured toreceive the second plastic extrudant and the third plastic extrudant andthe second end of the housing being configured to expel the mixture ofthe two extrudants through a plurality of outlets. The mixer furthercomprising a shaft having a first end and a second end. The first end ofthe shaft located proximate to the first end of the housing and thesecond end of the shaft located proximate to the second end of thehousing. The shaft being rotatable relative to the housing about anaxis. The mixer further comprising at least one projection coupled tothe shaft and rotatable with the shaft, the at least one projectionconfigured to orient the mixture of the two extrudants relative to theplurality of outlets in the second end of the housing. The mixer furthercomprising a thrust bearing configured to couple the second end of theshaft to the second end of the housing to permit expulsion of themixture in a non-linear pattern as the mixture is oriented relative tothe plurality of outlets.

[0008] In one exemplary embodiment, a plastic sheet is producedcomprising a first layer comprising a plastic extrudant and a secondlayer coupled to the first layer, the second layer comprising at leasttwo other plastic extrudants. The plastic extrudants of the second layerproduce a pattern wherein at least one of the plastic extrudants is atleast partially transparent such that both of the plastic extrudants arevisible in the second layer.

[0009] In one exemplary embodiment, a method for producing a plasticsheet, comprising the steps of extruding a first plastic extrudant toproduce a first layer, extruding a second plastic extrudant having anappearance, the appearance being at least partially transparent andincluding a first color, and extruding a third plastic extrudant havinganother appearance, the other appearance including a second color. Themethod further comprising mixing the second plastic extrudant and thethird plastic extrudant to produce a mixture, the mixture including anon-linear pattern. The method further comprising applying the mixtureof the second and third plastic extrudant to the first layer to producea second layer wherein the third plastic extrudant of the mixture isvisible within the second layer due to the appearance of the secondplastic extrudant of the mixture.

[0010] In another embodiment the step of mixing the second and thirdplastic extrudants in the preceding embodiment comprising the steps ofdividing the second plastic extrudant and the third plastic extrudant toproduce the mixture, positioning the mixture proximate to a selectionmember having a plurality of outlets, and selectively expelling themixture though the plurality of outlets such that a first portion of themixture is expelled through a first outlet at a first instance of timeand such that the first portion is not expelled from the first outlet ata second instance of time.

[0011] In another embodiment of the preceding embodiment, the step ofselectively expelling the mixture comprising the steps of rotating atleast one of either the selection member or the mixture relative to theother of the selection member or the mixture and applying a force to themixture to expel the first portion through the first outlet at the firsttime.

[0012] In yet another embodiment, a method for producing a plastic sheetcomprising the steps of extruding a first plastic extrudant having afirst appearance, the first appearance being at least partiallytransparent and including a first color, and extruding a second plasticextrudant having a second appearance, the second appearance including asecond color. The method further includes mixing the first plasticextrudant and the second plastic extrudant to produce a mixture having anon-linear pattern and producing a sheet from the mixture, the secondplastic extrudant being visible within the sheet due to the appearanceof the first plastic extrudant.

[0013] In another embodiment of the preceding embodiment the step ofmixing the first plastic extrudant and the second plastic extrudantcomprising the steps of dividing the first plastic extrudant and thesecond plastic extrudant to produce the mixture, positioning the mixtureproximate to a selection member having a plurality of outlets, andselectively expelling the mixture though the plurality of outlets suchthat a first portion of the mixture is expelled through a first outletat a first instance of time and such that the first portion is notexpelled from the first outlet at a second instance of time.

[0014] In a further embodiment, an apparatus for producing a plasticextrudant comprising a first extruder configured to extrude a firstplastic extrudant, a second extruder configured to extrude a secondplastic extrudant, the second plastic extrudant being at least partiallytransparent, and a mixer coupled to the first extruder and the secondextruder. The mixer being configured to produce a mixture of the firstplastic extrudant and the second plastic extrudant, the mixtureincluding a non-linear pattern. The apparatus further comprising a diecoupled to the mixer to receive the mixture of the first plasticextrudant and the second plastic extrudant to produce a layer. The layercontaining the non-linear pattern wherein the first plastic extrudant ofthe mixture is visible within the layer due to the second plasticextrudant of the mixture being at least partially transparent.

[0015] In yet a further embodiment of the preceding embodiment, themixer comprises a housing having a first end and a second end and aninterior region. The first end of the housing being configured toreceive the first plastic extrudant and the second plastic extrudant andthe second end of the housing being configured to expel the mixture ofthe two extrudants through a plurality of outlets. The mixer furthercomprising a shaft having a first end and a second end. The first end ofthe shaft located proximate to the first end of the housing and thesecond end of the shaft located proximate to the second end of thehousing, the shaft being rotatable relative to the housing about anaxis. The mixer further comprising at least one projection coupled tothe shaft and rotatable with the shaft, the at least one projectionconfigured to orient the mixture of the two extrudants relative to theplurality of outlets in the second end of the housing. The mixer furthercomprising a thrust bearing configured to couple the second end of theshaft to the second end of the housing to permit expulsion of themixture in a non-linear pattern as the mixture is oriented relative tothe plurality of outlets.

[0016] In another embodiment, a plastic sheet is produced comprising afirst plastic extrudant and a second plastic extrudant. The secondplastic extrudant is mixed with the first plastic extrudant to produce apattern. The second plastic extrudants is at least partially transparentsuch that both the second plastic extrudant and the first plasticextrudant are visible in the sheet.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a top view of a first exemplary embodiment of a plasticsheet of the present invention;

[0018]FIG. 2 is a cross-sectional view of the plastic sheet of FIG. 1along lines 2-2;

[0019]FIG. 3 is a block diagram representation of a co-extrusion processfor producing the plastic sheet illustrated in FIG. 1;

[0020]FIG. 4 is an exemplary cross-section of the plastic extrudantexiting the collection box of FIG. 3, the plastic extrudant consistingof two extrudants;

[0021]FIG. 5 is an exemplary cross-section of the plastic extrudantexiting the segmentor of FIG. 3;

[0022]FIG. 6 is a block diagram of a turbulator or mixer used in theco-extrusion process of FIG. 3;

[0023]FIG. 7 is a side view of a portion of the turbulator of FIG. 6;

[0024]FIG. 8 is a front view of a portion of the turbulator of FIG. 6illustrating the second end of the turbulator including the plurality ofoutlets;

[0025]FIG. 9 is the front view of FIG. 8 including a representation ofthe orientation of the plastic extrudant in the interior of theturbulator relative to the plurality of outlets in the second end; and

[0026]FIG. 10 is a block diagram representation of a co-extrusionprocess for producing a single layer plastic sheet having a patternformed therein.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0027] While the invention is susceptible to various modifications andalternative forms, exemplary embodiments thereof have been shown by wayof example in the drawings and will herein be described in detail. Itshould be understood, however, that there is no intent to limit theinvention to the particular forms disclosed, but on the contrary, theintention is to cover all modifications, equivalents, and alternativesfalling within the spirit and scope of the invention as defined by theappended claims.

[0028] Referring to FIGS. 1 and 2, a plastic sheet 100 is shown. Plasticsheet 100 includes a first layer 110 and a second layer 120. First layer110, in one embodiment, is composed of a thermoplastic material, such ashigh density polyethylene, which has been extruded. Second layer 120, inone embodiment, includes two or more thermoplastic materials, which havebeen extruded and combined in accordance with the present invention. Inalternative embodiments, first and second layers are formed of athermoset material. In FIGS. 1 and 2, second layer 120 includes amaterial 130 and a material 140. Second layer 120 may have any number ofadditional materials. The present invention is not intended to belimited to only two materials in the second layer 120.

[0029] Material 130 is a thermoplastic material which has a coloredappearance due to the addition of a colorant to the base plastic. In analternative embodiment, material 130 includes a colorant and anadditional additive to enhance the appearance of material 130. Exampleadditional additives include aluminum flakes or other types of flakesfor providing pearlescent effects, and flourescent dyes.

[0030] Material 140 is a thermoplastic material which has a coloredappearance due to the addition of a colorant to the base plastic. In analternative embodiment, material 140 includes a colorant and anadditional additive to enhance the appearance of material 140. Exampleadditional additives include aluminum flakes or other types of flakesfor providing pearlescent effects, and flourescent dyes.

[0031] In FIGS. 1 and 2, the amount of colorant added to material 130 issuch that the appearance of material 130 is opaque and the amount ofcolorant added to material 140 is such that the appearance of material140 is at least partially transparent or non-opaque. Due to the partialtransparent appearance of material 140, material 130 is visible withinsecond layer 120 by an observer through an outer surface 150 of plasticsheet 100.

[0032] Referring to FIGS. 1 and 2, material 130 creates a pattern insecond layer 120, such as swirl pattern 153. Material 130 is dividedinto pattern components or swirls 154, 156, 158, 160, 162, 164 and 166.Swirls 154, 156, 158, 160, 162, 164 and 166 are located at variouspositions within second layer 120, such as: at outer surface 150, at abottom surface 168 and at intermediate positions between outer surface150 and bottom surface 168. Referring to FIG. 2, swirl 154 and swirl 160are located at a first intermediate position 170. Swirl 156 is locatedat a second intermediate position 172. Swirl 158 is located at bottomsurface 168. The capacity to see the pattern 153 in material 130 eventhough swirls 154, 156, 158, 160, 162, 164 and 166 are at varyingpositions or heights in second layer 120 gives plastic sheet 100 a depthcharacteristic. If the appearance of material 140 was not at leastpartially transparent then only the pattern components which are locatedat outer surface 150 would be visible to an observer.

[0033] Plastic sheet 100 can be manufactured from any suitablethermoplastic material, such as polyethylene, high density polyethyleneincluding a high molecular weight polyethylene, ABS (AcrylonitrileButadiene Styrene) or polystyrene. In one embodiment, plastic sheet 100has a thickness 174 in the range of 0.050 inches to 0.500 inches. Inanother embodiment, thickness 174 is in the range of 0.150 inches to0.300 inches. In a preferred embodiment, thickness 174 is in the rangeof 0.100 inches to 0.350 inches. In one embodiment, second layer 120 hasa thickness 175 in the range of 0.050 inches to 0.300 inches. In anotherembodiment thickness 175 is in the range of 0.050 inches to 0.250inches. In the preferred embodiment thickness 175 is 0.250 inches. Inone embodiment, plastic sheet 100 has a width 176 in the range of 4 to90 inches. In another embodiment, width 176 is in the range of 2 to 100inches. In yet another embodiment, width 176 is in the range of 12 to 80inches.

[0034] Referring to FIG. 3, an exemplary embodiment 200 of the apparatusand process for manufacturing plastic sheet 100 is shown. Extruder 202extrudes a plastic extrudant 204 which corresponds to the plastic infirst layer 110. Extruder 202 is a 2 inch extruder available from Welex,Inc. located at 850 Jolly Road, Blue Bell, Pa. 19422. Plastic extrudant204 is feed into a Co-Extrusion Block 206 available from Davis Standardlocated at #1 Extrusion Drive, Pawcatuck, Conn. 06379. Co-ExtrusionBlock 206 includes a plurality of channels one of which receives plasticextrudant 204.

[0035] Extruder 208 extrudes a plastic extrudant 210 which correspondsto the plastic in material 140 in second layer 120 in FIGS. 1 and 2.Extruder 208 is a 3.5 inch extruder available from Davis Standard.Extruder 212 extrudes a plastic extrudant 214 which corresponds to theplastic in material 130 in second layer 120 in FIGS. 1 and 2. Extruder212 is a 2.5 inch extruder available from Welex, Inc.

[0036] Plastic extrudants 210 and 214 are presented to a mixer 225 toproduce a mixture 232. Plastic extrudants 210 and 214 are collected in acollection box 216, available from Davis Standard. Collection box 216produces a plastic extrudant or mixture 218 which includes both plasticextrudant 210 and plastic extrudant 214. Referring to FIG. 4, plasticextrudant 210 and plastic extrudant 214 are generally segregated toseparate portions of plastic extrudant 218.

[0037] In alternative embodiments, mixture 218 further includesadditional plastics having appearances differing from plastic extrudants210 and 214. In one embodiment, extruder 213 extrudes a plasticextrudant 215 which has an appearance differing from plastic extrudants210 and 214. Plastic extrudant 215 is collected in collection box 216along with plastic extrudants 210 and 214. Extruder 213 is manufacturedby and available from Welex, Inc. In another embodiment, extruder 217extrudes a plastic extrudant 219 having an appearance differing fromplastic extrudants 210, 214 and 215. Plastic extrudant 219 is collectedin collection box 216 along with plastic extrudants 210, 214 and 215.Extruder 217 is available from Welex, Inc.

[0038] In one embodiment, a green camouflage pattern is produced assecond layer 120 with the mixing of the following three extrudants.Extruder 208 produces a plastic extrudant or mixture containing 99.5% ofhigh density polyethylene (such as HMWPE) and 0.5% of color concentrate,the color being olive drab. Normally to produce an opaque extrudant, 4%of the mixture is colorant and 96% is HMWPE. By reducing the percentageof colorant used, the resultant extrudant or mixture is at leastpartially transparent.

[0039] In one embodiment, an ultra-violet inhibitor (UVI) stabilizer isadded to the extrudant or mixture for outdoor applications of sheet 100.Extruder 208 is a 3.5 inch extruder available from Davis-Standardoperating at 90 rpm (revolutions per minute) and 350-400 pph (pounds perhour). The heat profile for the extrudant is a normal profile for a 10HLMI (high load melt index) HMWPE material with a temperature between420° F. and 450° F. The extrudant produced by extruder 208 is collectedin collection box 216.

[0040] Extruder 212 produces a plastic extrudant or mixture containing96% HMWPE and 4% color concentrate, the color being black. Due to the 4%color concentrate, the extrudant is opaque. Extruder 212 is a 2.5 inchextruder available from Welex, Inc. operating at 2 rpm. The extrudantproduced by extruder 212 is collected in collection box 216.

[0041] Extruder 213 produces a plastic extrudant or mixture containing96% HMWPE and 4% color concentrate, the color being dark green. Due tothe 4% color concentrate, the extrudant is opaque. Extruder 213 is a 2.0inch extruder available from Welex, Inc. operating at 38 rpm. The heatprofile for the extrudant is a normal profile for a 10 HLMI HMWPEmaterial with a temperature between 420° F. and 450° F. The extrudantproduced by extruder 213 is collected in collection box 216.

[0042] The extrudant exiting collection box 216 is composed of the atleast partially transparent olive drab extrudant of extruder 208, theblack extrudant of extruder 212, and the dark green extrudant ofextruder 213. The at least partially transparent olive drab extrudantcomprises the majority of the extrudant exiting collection box 216 dueto the operating speeds of extruders 208, 212, 213. Extruder 208 whichproduces the olive drab extrudant is operating at 90 rpm and is a 3.5inch extruder. Extruder 212 which produces the black extrudant isoperating at 2 rpm and is a 2.5 inch extruder. Extruder 213 whichproduces the dark green extrudant is operating at 38 rpm and is a 2.0inch extruder.

[0043] Various color variations can be achieved in second layer 120through variations in the operating parameters of extruders 208, 212,213 and the types and amounts of colorants used in each extruder. Forexample, in another embodiment, an arid camouflage pattern is producedwith the same parameters as for green camouflage except that the speedof extruder 213, corresponding to the flow rate for the green extrudant,is decreased from 38 rpm to 16 rpm and the speed of extruder 212,corresponding to the flow rate for the black extrudant, is increasedfrom 2 rpm to 4 rpm to produce a tan coloration.

[0044] Referring to FIG. 3, plastic extrudant or mixture 218 ispresented to a segmentor 220 which divides plastic extrudant 210 andplastic extrudant 214 to produce a plastic extrudant or mixture 222,generally as shown in FIG. 5. Plastic extrudant or mixture 222 includesgenerally distinct segments of plastic extrudants 210 and 214. In oneembodiment, segmentor 220 is a homogeneous mixer available fromPrecision Weld located at 4701 Beam Road, Charlotte, N.C. 28217. Thehomogenous mixer is used in general extrusion applications to equal outcolor and temperature variations in the extrudant or melt. This isaccomplished by stationary fins in the mixer which fold the extrudant tomix the extrudant. In the application of the present invention, asmaller number of fins are used than in the general usage of ahomogenous mixer. By reducing the number of fins, the extrudant ormixture 222 has the segmented appearance of FIG. 5 instead of ahomogeneous appearance. In one embodiment, the homogenous mixture has 9fins for general applications. To produce the segmented appearance ofplastic extrudant 222, fewer than 9 fins are used. In preferredembodiments, 7 to 8 fins are used to segment plastic extrudants 210 and214. In one preferred embodiment, 7 fins are used to segment plasticextrudants 210 and 214.

[0045] Plastic extrudant or mixture 222 upon exiting segmentor 220 ispresented to a turbulator 230 which expels a plastic extrudant ormixture 232 which is presented to co-extrusion block 206. Plasticextrudant or mixture 232 enters co-extrusion block 206 in a separatechannel from plastic extrudant 204. The channel containing plasticextrudant or mixture 232, in one embodiment, is above the channelcontaining plastic extrudant 206 such that second layer 120 is on top offirst layer 110 in plastic sheet 100. In another embodiment, the channelcontaining plastic extrudant or mixture 232, is below the channelcontaining plastic extrudant 204 such that second layer 120 is belowfirst layer 110 in plastic sheet 100. In yet another embodiment,extrudant or mixture 232 is fed into two channels in co-extrusion block206 such that plastic sheet 100 is comprised of three layers, a baselayer including plastic extrudant 204 and a top and bottom layerincluding plastic extrudant or mixture 232. Plastic extrudants 204 and232 exit co-extrusion block 206 as plastic extrudant 236 and are fed toa sheet die 234. Die 234 produces plastic extrudant 238 which is rolledinto sheet 100 by rollers 240.

[0046] Plastic sheet 100 is molded into an article for use by an enduser. Examples include accessories for outdoor play equipment, such asslides, hunting accessories, such as gun cases, or canoes.

[0047] Referring to FIG. 6, turbulator 230 includes a housing 240defining an interior region 241, a first end 242, a second end 244, andan orientation unit 246. A turbulator 230 is available fromPrecision-Weld located at 4701 Beam Road, Charlotte, N.C. 28217.However, the turbulator available from Precision-Weld must be modifiedin accordance with the present invention to produce plastic extrudant ormixture 232 and hence plastic sheet 100.

[0048] Referring to FIG. 7, orientation unit 246 includes a shaft 248and projections or fins 250 extending radially from an outer surface 252in shaft 248. The projections 250 and shaft 248 rotate along a centralaxis 251 of turbulator 230 due to the movement of plastic extrudant 222in direction 223. As shaft 248 rotates, projections 250 engage plasticextrudant 222 and cause plastic extrudant 222 to rotate.

[0049] Second end 244 of turbulator 230 includes a plate or selectionmember 254 containing a plurality of outlets 256 and a thrust bearing258 interposed between plate 254 and shaft 248. Thrust bearing 258assists in the rotation of shaft 248, projections 250 and plasticextrudant or mixture 222. In alternative embodiments, additional formsof bearings are used.

[0050] In one exemplary embodiment, thrust bearing 258 is comprised of afirst bearing 260 and a second bearing 262. Both first bearing 260 andsecond bearing 262 are positioned within a recess 264 in plate orselection member 254. First bearing 260 is positioned next to an arcuatesurface 266 of recess 264. Second bearing 262 is positioned betweenfirst bearing 260 and an arcuate surface 268 of shaft 248. First bearing260 and second bearing 262 contact each other and pivot independent ofeach other. In a preferred embodiment, first bearing 260 and secondbearing 262 are spherical and are 0.34″ in diameter.

[0051] Referring to FIGS. 7 and 8, the plurality of outlets 256 extendfrom a first surface 270 of plate or selection member 254 locatedadjacent the interior region 241 of turbulator 230 through plate orselection member 254 to a second surface 272 of plate or selectionmember 254. The plurality of outlets 256, permit portions of plasticextrudant 222 to be expelled from turbulator 230 as plastic extrudant232. In one embodiment, plastic extrudant 222 is rotated relative to theplurality of outlets, to selectively expel portions of plastic extrudant222 at various points in time. In another embodiment, the plurality ofoutlets are rotated due to the rotation of the selection member, toselectively expel portions of plastic extrudant 222 at various points intime.

[0052] Referring to FIG. 8, the plurality of outlets 256 are spacedaround end plate 254. The size, shape and locations of the plurality ofoutlets are some factors which dictate the portions of plastic extrudant222 which are expelled from turbulator 230 to produce the pattern ofplastic extrudant 232. Additional factors include the rate of rotationof plastic extrudant 222, and the flow rate of plastic extrudant 222. Ina preferred embodiment, plastic extrudant 222, shaft 248 and projections250 rotate at approximately 1 rpm.

[0053] In one embodiment, plate 245 has an outer diameter 280 of 4.235inches. The second surface 272 continuing the plurality of outlets 256is ring shaped with an inner diameter 282 of 1.500 inches and an outerdiameter 284 of 3.500 inches. The plurality of outlets 256 includes aplurality of first outlets 286 having a circular cross section having adiameter 288 of 0.5625 inches and being centered 1.125 inches from thecentral axis 251 of turbulator 230. The plurality of outlets furtherincludes a plurality of second outlets 290 having a circular crosssection having a diameter 292 of 0.3125 inches and being centered 1.3125inches from the central axis 251 of turbulator 230.

[0054] Referring to FIG. 9, the operation of turbulator 230 isillustrated for a partial rotation of shaft 248, projections 250 andplastic extrudant 222. Plastic extrudant 222 is positioned in turbulator230 and is being oriented in time due to the rotation of shaft 248 andprojections 250.

[0055] With reference to FIG. 9 the portions of plastic extrudant 222,refer to a cylindrical column of plastic extrudant 222 extending backinto turbulator 230. As such, when it is stated that a particularportion has been expelled from turbulator 230, in reality only a portionof the particular portion has been expelled. Additionally, eachparticular portion may contain a variety of appearances at variousinstances of time due to the types of plastic, extrudants 210 and 214,which comprise that particular portion. The types of plastic, extrudants210 and 214, which comprise various portions of a particular portion isgoverned by a number of factors including the operational parameters ofextruders 208 and 212, the operational parameters of segmentor 220including the number of fins used, and the operational parameters ofturbulator 230, including the rate of rotation of the shaft 248. Thepreferred rates to produce a green camouflage and an arid camouflage areprovided above.

[0056] Once the process is running at generally constant rates andparameters, the portions of plastic extrudant expelled from turbulator230, repeat every revolution of plastic extrudant 222 to form multipleinstances of swirl pattern 153 in second layer 120. As such, the swirlpattern 153 in plastic sheet 100 repeats itself along a length 173 ofsecond layer 120. In one embodiment, swirl pattern 153 repeats itself3.5 times along length 173 when second layer 120 has a length of 100inches and a thickness of 0.25 inches.

[0057] Referring to FIG. 9, at a first instance in time a first portion300 of plastic extrudant 222 is oriented or positioned within the extentof first outlet 286 a and a second portion 302 of plastic extrudant 222is oriented or positioned outside the extent of both first outlets 286and second outlets 290. As such at a first instance of time, firstportion 300 is expelled from turbulator 230 through first outlet 286 aand second portion 302 is not expelled.

[0058] At a second instance in time, first portion 300 and secondportion 302 have been rotated to second locations indicated by referencenumerals 300′ and 302′. At the second instance in time, first portion300′ is oriented or positioned outside the extent of first outlets 286and second outlets 290 and second portion 302′ is oriented or positionedwithin the extent of first outlet 286 a. As such, at the second instancein time, first portion 300′ is not expelled from turbulator 230 andsecond portion 302′ is expelled through first outlet 286 a.

[0059] At a third instance in time first portion 300′ and second portion302′ have been rotated to third locations indicated by referencenumerals 300″ and 302″. At the third instance in time, first portion300″is oriented or positioned within the extent of second outlet 290 aand second portion 302″ is oriented or positioned within the extent offirst outlet 286 a. As such, at the third instance in time, firstposition 300″ and second portion 302″ are both being expelled fromturbulator 230 through second outlet 290 a and first outlet 286 a,respectively.

[0060] At a later instance of time first portion 300″ and second portion302″ return to their positions in the first instance of time such thatthe first portion is oriented or positioned within the extent of firstoutlet 286 a and the second portion is oriented or positioned outsidethe extent of both first outlets 286 and second outlets 290. At thelater instance of time a complete instance of pattern 153 has beenexpelled from turbulator 230 and a second instance of pattern 153 isbeginning to be expelled from turbulator 230.

[0061] In an alternative embodiment, a single layer sheet 400 having apattern generally identical to pattern 153 is produced. Referring toFIG. 10, an exemplary embodiment 402 of the apparatus and process formanufacturing plastic sheet 400 is shown. The components used and methodof operation of embodiment 402 is generally identical to embodiment 200,shown in FIG. 3. As such, like numerals will be used for similarcomponents and extrudants in embodiments 402 and 200. Details concerningthe similar components and extrudants are provided in the detaileddescription of embodiment 200.

[0062] Referring to FIG. 10, the mixture 232 exits turbulator 230 and ispresented to die 404. Die 404 produces plastic extrudant 406 which isrolled into sheet 400 by rollers 240. The pattern formed in sheet 400 isgenerally identical to pattern 153 formed in sheet 100, except that thepattern of sheet 400 is visible both through an outer or top surface anda bottom surface due to the absence of an opaque base layer.

[0063] While the invention has been illustrated and described in detailin the drawings and foregoing description, such illustration anddescription is to be considered as exemplary and not restrictive incharacter, it being understood that only exemplary embodiments have beenshown and described and that all changes and modifications that comewithin the spirit of the invention are desired to be protected.

I claim:
 1. An apparatus for producing a non-linear pattern from amixture of at least two extrudants in an extrusion process; theapparatus comprising: a housing having a first end and a second end andan interior region, the first end adapted to receive the mixture of atleast two extrudants and the second end configured to expel the mixtureof the at least two extrudants in a non-linear pattern, the second endincluding a plurality of outlets to selectively expel the mixture; ashaft having a first end and a second end, the first end locatedproximate to the first end of the housing and the second end locatedproximate to the second end of the housing, the shaft being rotatablerelative to the housing about an axis; at least one projection coupledto the shaft and rotatable with the shaft, the at least one projectionconfigured to orient the mixture relative to the plurality of outlets inthe second end of the housing; and a thrust bearing configured to couplethe second end of the shaft to the second end of the housing to permitthe expulsion of the mixture in a non-linear pattern as the mixture isoriented relative to the plurality of outlets.
 2. The apparatus of claim1, wherein the thrust bearing comprises a first bearing and a secondbearing configured to be pivotable relative to the first bearing.
 3. Theapparatus of claim 1, wherein the plurality outlets includes a pluralityof first outlets having a first diameter and a plurality of secondoutlets having a second diameter.
 4. The apparatus of claim 3, whereinthe diameter of the plurality of first outlets is 0.5625 inches and theplurality of first outlets are centered on a circle having a radius of1.125 inches from the axis of the shaft and wherein the diameter of theplurality of second outlets is 0.3125 inches and the plurality of secondoutlets are centered on a circle having a radius of 1.125 inches fromthe axis of the shaft.
 5. The apparatus of claim 1, wherein the mixtureis oriented such that a first portion of the mixture is expelled througha first outlet of the plurality of outlets at a first instance of timeand such that the first portion is not expelled from the first outlet ata second instance of time.
 6. The apparatus of claim 5, wherein thefirst portion is expelled through the first outlet of the plurality ofoutlets at a third instance of time, the mixture having made a firstcomplete rotation about the axis in the time elapsed between the firstinstance of time and the third instance of time.
 7. The apparatus ofclaim 6, wherein the non-linear pattern is a repeating pattern.
 8. Theapparatus of claim 7, wherein the non-linear pattern repeats for everycomplete revolution of the mixture.
 9. An apparatus for producing amulti layer plastic extrudant; the apparatus comprising: a firstextruder configured to extrude a first plastic extrudant; a secondextruder configured to extrude a second plastic extrudant, the secondplastic extrudant being at least partially transparent; a third extruderconfigured to extrude a third plastic extrudant; a mixer coupled to thesecond extruder and the third extruder and configured to produce amixture of the second plastic extrudant and the third plastic extrudant,the mixture including a non-linear pattern; and a co-extrusion blockcomprising a first channel and a second channel, wherein the firstchannel is coupled to the first extruder to receive the first plasticextrudant to produce a first layer and wherein the second channel iscoupled to the mixer to receive the mixture of the second plasticextrudant and the third plastic extrudant to produce a second layer, thesecond layer containing the non-linear pattern wherein the third plasticextrudant of the mixture is visible within the second layer due to thesecond plastic extrudant of the mixture being at least partiallytransparent.
 10. The apparatus of 9, wherein the mixer comprises: ahousing having a first end and a second end and an interior region, thefirst end configured to receive the second plastic extrudant and thethird plastic extrudant and the second end configured to expel themixture of the two extrudants through a plurality of outlets; a shafthaving a first end and a second end, the first end located proximate tothe first end of the housing and the second end located proximate to thesecond end of the housing, the shaft being rotatable relative to thehousing about an axis; at least one projection coupled to the shaft androtatable with the shaft, the at least one projection configured toorient the mixture of the two extrudants relative to the plurality ofoutlets in the second end of the housing; and a thrust bearingconfigured to couple the second end of the shaft to the second end ofthe housing to permit expulsion of the mixture in a non-linear patternas the mixture is oriented relative to the plurality of outlets.
 11. Theapparatus of claim 10, wherein the thrust bearing comprises a firstbearing and a second bearing configured to be pivotable relative to thefirst bearing.
 12. The apparatus of claim 10, wherein the pluralityoutlets includes a plurality of first outlets having a first diameterand a plurality of second outlets having a second diameter.
 13. Theapparatus of claim 12, wherein the diameter of the plurality of firstoutlets is 0.5625 inches and the plurality of first outlets are centeredon a circle having a radius of 1.125 inches from the axis of the shaftand wherein the diameter of the plurality of second outlets is 0.3125inches and the plurality of second outlets are centered on a circlehaving a radius of 1.125 inches from the axis of the shaft.
 14. Aplastic sheet, comprising: a first layer comprising a plastic extrudant;and a second layer coupled to the first layer, the second layercomprising at least two other plastic extrudants, wherein the otherplastic extrudants produce a pattern and wherein at least one of theother plastic extrudants is at least partially transparent such thatboth of the other plastic extrudants are visible in the second layer.15. The plastic sheet of claim 14, wherein the at least one of the otherplastic extrudants of the second layer has an appearance, the appearanceof the at least one of the other plastic extrudants having a firstcolor, and wherein the other plastic extrudant of the at least other twoplastic extrudants of the second layer has another appearance, theappearance of the other plastic extrudant of the at least other twoplastic extrudants having a second color.
 16. The plastic sheet of claim14, wherein the pattern is a non-linear pattern.
 17. The plastic sheetof claim 15, wherein the first and second layers are made ofpolyethylene and wherein the pattern is a non-linear pattern.
 18. Theplastic sheet of claim 17, wherein the second layer is comprised of atleast three plastic extrudants and wherein the at least three plasticextrudants produce the non-linear pattern.
 19. The plastic sheet ofclaim 17, wherein the second layer is comprised of at least four plasticextrudants and wherein the at least four plastic extrudants produce thenon-linear pattern.
 20. The plastic sheet of claim 15, wherein the firstand second layers are made of high density polyethylene and wherein thepattern is a non-linear pattern.
 21. The plastic sheet of claim 15,wherein the first and second layers are made of Acrylonitrile ButadieneStyrene and wherein the pattern is a non-linear pattern.
 22. The plasticsheet of claim 15, wherein the first and second layers have a combinedthickness in the range of 0.100 inches to 0.350 inches.
 23. The plasticsheet of claim 15, wherein the second layer is made of polystyrene. 24.A method for producing a plastic sheet, comprising the steps of:extruding a first plastic extrudant to produce a first layer; extrudinga second plastic extrudant having an appearance, the appearance being atleast partially transparent and including a first color; extruding athird plastic extrudant having another appearance, the other appearanceincluding a second color; mixing the second plastic extrudant and thethird plastic extrudant to produce a mixture, the mixture including anon-linear pattern; and applying the mixture of the second and thirdplastic extrudant to the first layer to produce a second layer whereinthe third plastic extrudant of the mixture is visible within the secondlayer due to the appearance of the second plastic extrudant of themixture.
 25. The method of claim 24 wherein the step of mixing thesecond and third plastic extrudants comprises the steps of: dividing thesecond plastic extrudant and the third plastic extrudant to produce themixture; positioning the mixture proximate to a selection member havinga plurality of outlets; and selectively expelling the mixture though theplurality of outlets such that a first portion of the mixture isexpelled through a first outlet at a first instance of time and suchthat the first portion is not expelled from the first outlet at a secondinstance of time.
 26. The method of claim 25, wherein the step ofselectively expelling the mixture comprises the steps of: rotating atleast one of either the selection member or the mixture relative to theother of the selection member or the mixture; and applying a force tothe mixture to expel the first portion through the first outlet at thefirst time.
 27. The method of claim 26, wherein the mixture is rotatedrelative to the selection member by providing a rotatable shaftpositioned adjacent the mixture, the shaft including at least oneprojection extending from the shaft, and by engaging the mixture withthe projection to cause the rotation of the mixture relative to theselection member.
 28. A method for producing a plastic sheet, comprisingthe steps of: extruding a first plastic extrudant having a firstappearance, the first appearance being at least partially transparentand including a first color; extruding a second plastic extrudant havinga second appearance, the second appearance including a second color;mixing the first plastic extrudant and the second plastic extrudant toproduce a mixture having a non-linear pattern; and producing a sheetfrom the mixture, the second plastic extrudant being visible within thesheet due to the appearance of the first plastic extrudant.
 29. Themethod of claim 28, wherein the step of mixing the first plasticextrudant and the second plastic extrudant comprises the steps of:dividing the first plastic extrudant and the second plastic extrudant toproduce the mixture; positioning the mixture proximate to a selectionmember having a plurality of outlets; and selectively expelling themixture though the plurality of outlets such that a first portion of themixture is expelled through a first outlet at a first instance of timeand such that the first portion is not expelled from the first outlet ata second instance of time.
 30. The method of claim 29, wherein the stepof selectively expelling the mixture comprises the steps of: rotating atleast one of either the selection member or the mixture relative to theother of the selection member or the mixture; and applying a force tothe mixture to expel the first portion through the first outlet at thefirst time.
 31. The method of claim 30, wherein the mixture is rotatedrelative to the selection member by positioning a rotatable shaftadjacent the mixture, the shaft including at least one projectionextending from the shaft, and by engaging the mixture with theprojection to cause the rotation of the mixture relative to theselection member.
 32. An apparatus for producing a plastic extrudant;the apparatus comprising: a first extruder configured to extrude a firstplastic extrudant; a second extruder configured to extrude a secondplastic extrudant, the second plastic extrudant being at least partiallytransparent; a mixer coupled to the first extruder and the secondextruder and configured to produce a mixture of the first plasticextrudant and the second plastic extrudant, the mixture including anon-linear pattern; and a die coupled to the mixer to receive themixture of the first plastic extrudant and the second plastic extrudantto produce a layer, the layer containing the non-linear pattern whereinthe first plastic extrudant of the mixture is visible within the layerdue to the second plastic extrudant of the mixture being at leastpartially transparent.
 33. The apparatus of 32, wherein the mixercomprises: a housing having a first end and a second end and an interiorregion, the first end configured to receive the first plastic extrudantand the second plastic extrudant and the second end configured to expelthe mixture of the two extrudants through a plurality of outlets; ashaft having a first end and a second end, the first end locatedproximate to the first end of the housing and the second end locatedproximate to the second end of the housing, the shaft being rotatablerelative to the housing about an axis; at least one projection coupledto the shaft and rotatable with the shaft, the at least one projectionconfigured to orient the mixture of the two extrudants relative to theplurality of outlets in the second end of the housing; and a thrustbearing configured to couple the second end of the shaft to the secondend of the housing to permit expulsion of the mixture in a non-linearpattern as the mixture is oriented relative to the plurality of outlets.34. The apparatus of claim 33, wherein the thrust bearing comprises afirst bearing and a second bearing configured to be pivotable relativeto the first bearing.
 35. The apparatus of claim 33, wherein theplurality outlets includes a plurality of first outlets having a firstdiameter and a plurality of second outlets having a second diameter. 36.The apparatus of claim 35, wherein the diameter of the plurality offirst outlets is 0.5625 inches and the plurality of first outlets arecentered on a circle having a radius of 1.125 inches from the axis ofthe shaft and wherein the diameter of the plurality of second outlets is0.3125 inches and the plurality of second outlets are centered on acircle having a radius of 1.125 inches from the axis of the shaft.
 37. Aplastic sheet, comprising: a first plastic extrudant; and a secondplastic extrudant mixed with the first plastic extrudant to produce apattern, wherein the second plastic extrudants is at least partiallytransparent such that both the second plastic extrudant and the firstplastic extrudant are visible in the sheet.
 38. The plastic sheet ofclaim 37, wherein the first plastic extrudant has an appearance, theappearance of the first plastic extrudant having a first color, andwherein the second plastic extrudant has another appearance, theappearance of the second plastic extrudant having a second color. 39.The plastic sheet of claim 37, wherein the pattern is a non-linearpattern.
 40. The plastic sheet of claim 38, wherein the first and secondplastic extrudants are made of polystyrene and wherein the pattern is anon-linear pattern.
 41. The plastic sheet of claim 38, wherein the sheetis comprised of at least three plastic extrudants and wherein the atleast three plastic extrudants produce the non-linear pattern.
 42. Theplastic sheet of claim 38, wherein the sheet is comprised of at leastfour plastic extrudants and wherein the at least four plastic extrudantsproduce the non-linear pattern.
 43. The plastic sheet of claim 38,wherein the first and second plastic extrudants are made of high densitypolyethylene and wherein the pattern is a non-linear pattern.
 44. Theplastic sheet of claim 38, wherein the first and second extrudants aremade of Acrylonitrile Butadiene Styrene and wherein the pattern is anon-linear pattern.
 45. The plastic sheet of claim 38, wherein the firstand second plastic extrudants are made of polyethylene and wherein thepattern is a non-linear pattern.